2. For the shortbread layer: beat butter until soft and creamy, add sugar and flour and mix until it forms a dough (do not overbeat). Pat into an even layer in prepared pan and bake for 20-25 minutes until golden brown.

3. While shortbread is baking, prepare brownies: melt the butter in a small, heavy-based saucepan, then stir in the cocoa until blended and set aside.

4. Beat the eggs until light and fluffy. Gradually add the sugar and stir in the chocolate mixture. Sift the flour over the top and fold it into the mixture. Fold in the nuts, if using.

5. Once the shortbread layer is done, pour the brownie mixture over it in an even layer and bake for 30-35 minutes, or until just cooked through and springy to the touch.

6. Place pan in the refrigerator to cool. Once brownies are firm, heat caramel bits and heavy cream until uniformly liquid. Pour melted caramel over brownies and spread evenly. Refrigerate again until firm. (Do not cheat this step.)

7. Grab the ends of the foil and remove from pan. Peel the foil off the sides and bottom and place the brownies on a cutting board and cut into thin bars. Melt chocolate for enrobing and dip bars, placing on a wax paper lined baking sheet until chocolate is set.